Refrigeration apparatus



Sept 25, 1933. F. I.. TARLETON n l,28,67

REFRIGERATION APPARATUS Filed Jan. 21, 1952 2 sheets-sheet 1 sV va E I -w/m/fssff FIG E /N VENTO/I A TTOR/VEY Sept. 26, 1933. F. L. TARLETON REFRIGERATION APPARATUS 2 vsheets-sheet 2 Filed Jan. 2l, 1932 ma ae f IIIII /N VEA/TOR FEEDER@ ,I .THQLE-voN.

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ATTORNEY Patented Sept. 26, 1933 REFRIGERATION APPARATUS Frederic L. Tarleton, Springfield, Mass., assignor to Westinghouse Electric & Manufacturing Company, a corporation of Pennsylvania Application January 21, 1932. Serial VNo. 587,973

7 Claims. (Cl. 62--126) My invention relates to refrigerating apparatus, and particularly to a heat absorber or evaporator of the flooded type adapted to be utilized in mechanical refrigerating apparatus.

Evaporators of the flooded type comprise generally a main header, or boiler, and one or more closed refrigerant containing chambers which open. into the header. A refrigerant inlet conduit'is provided for conveying liquid refrigerant 1,0 from the condenser of the refrigerating system to the evaporator. A refrigerant discharge conduit is also provided for conveying gaseous refrigerant from the evaporator to the compressor, which refrigerant is boiled off the stored refrigerant in the evaporator and is drawn back to the compressor by the suction thereof. In evaporators, as heretofore commonly constructed, both the inlet and discharge conduits extend through the header, and the discharge conduit is usually disposed a small distance above the normal level of the liquid in the evaporator so that only gaseous refrigerant is embodied therein.

The inlet conduit is usually disposed a short distance below the refrigerant level in the evaporator, and a slight circulation of liquid in the header and chambers is thereby effected.

I have found, however, that by effecting a forced circulation of refrigerant in the evapo.- rator, that more equal vaporization of liquid refrigerant in all parts of the evaporator is obtained, and, therefore,'more even temperatures are maintained in the evaporator and in the refrigerator cabinet.

It is an object of my invention, therefore, to r ensure a forced circulation of refrigerant to substantially all the parts of a refrigerator evaporator when the refrigerator unit is operating.

I have also found in refrigerating systems especially those in which a refrigerant and oil are 40 utilized which are not miscible in all proportions over the operating temperatures and pressures present in an ordinary refrigerating machine, that oil is separated from refrigerant in the evaporator of a refrigerating machine; and the increase in viscosity of the oil due to the low temperature to which it is subjected tends to cause greater adherence to the Walls of the evaporator, usually at points remote from the header, because circulation of refrigerant is at a minimum at these points in evaporators as commonly constructed. This condition causes a part of the evaporator to have low heat transfer qualities, as the heavy oil film acts as a heat insulation between the refrigerator, and the evaporator is, therefore, inefficient. In evaporators in which the inlet conduit conveys liquid refrigerant to the evaporator header, the circulation of refrigerant is very slight in the parts of the evaporator remotefrom the header, and the thick oil which adheres tothees Aof the evaporator is not returned to the compressor and motor until it is thinned by heat and rises to the header. Two disadvantages therefore arise, first, the oil prevents good heat transfer from the refrigerating cabinet to the refrigerant, and secondly, large quantities of oil are at least temporarily not available for lubricating the Working parts of the refrigerating machine.

It is another object of my invention, therefore, to prevent oil logging in an evaporator of the flooded type.

It is another object of my invention to utilize one of the refrigerant-containing chambers depending from the main header to conveyincoming refrigerant directly to the bottom of the evaporator, or to a point remote from the main header, and to provide a second header which connects all the chambers depending from the main header, including the chamber in which incoming refrigerant is contained so that liquid refrigerant is conveyed by means of the second header to all the chambers at points remote from the header, so that forced circulation of refrigerant toward the header is effected.

It is still another object of my invention to provide an evaporator which is cheap and easy to assemble, and which will overcome the aforementioned diiculties and disadvantages.

These and other objects are effected by my invention, as will be apparent from the following description and claims taken in connection with the accompanying drawings forming a part -of this application, in which:

vrator of the flooded type, illustrating an embodiment of my invention as applied to an evaporator of the type shown in Fig. 1.

Fig. 3 is a bottom plan View of the evaporator 10 of the flooded type shown in Fig. 2;

Fig. 4 is a front sectional view of the evaporator;

Fig. 5 is an enlarged section of the evaporator illustrating the construction of the lower header 10 and showing the path of liquid refrigerant in the embodiment of my invention shown; and,

Fig. 6 is an end view of the evaporator before it is bent to form a freezing chamber.

Although I have shown my invention as ap- 1,10

plied to a sheet metal welded evaporator having a boiler or header, it is understood/that I do not wish to be limited either to a welded sheet metal evaporator, or to a header, except insofar as set forth in the appended claims.

It is desirable for the discharge conduit from a flooded evaporator to be disposed above the level of the liquid in the evaporator, so that liquid refrigerant is not drawn back to the compressor. Since it is desirable to circulate refrigerant in relatively large quantities to substantially all parts of an evaporator, the refrigerant is conveyed to the evaporator at a point or points remote from the point at which it is withdrawn, so that circulation toward the withdrawal point is effected.

In the specific embodiment of my invention shown in the drawings, the discharge conduit has its end passing through a main header at the top of the evaporator so that it is disposed above the normal level of liquid, and, therefore, con-y veys only vapor which is withdrawn by the suction pressure of the refrigerator compressor. The passageways of the evaporator all open into a main header, and a lower header is also provided communicating with all of the passageways. The inlet conduit which conveys liquid refrigerant to the evaporator also enters through the main header, and is connected directly preferably by welding to one of the evaporator passageways, which passageway is therefore not in direct communication with the main upper header.

Liquid refrigerant is conveyed down the passageway to the lower header, out through the lower header to the passageways, and up the passageways to the main header. This flow i s clearly illustrated by the arrows of Fig. 2. Circulation of refrigerant in the evaporator is ensured as long as refrigerant liquid is being delivered to the evaporator, whereby oil logging is less whether refrigerant is being delivered to the evaporator or not because the oil film in the evaporator is lessened each time the refrigerating unit operates. Forced circulation of refrigerant also affects more even temperatures inthe evaporator while the refrigerant fiuid is being delivered thereto and circulated.

Referring specifically to the drawings for a detailed description of my invention, a complete.

refrigerating unit is illustrated in Fig. 1 comprising generally a compressor 1, anda motor 2 for driving the compressor both of which are contained in a huid-tight casing 3. Refrigerant cornpressed by the compressor 1 is delivered to a condenser 4, where it is cooled and condensed, the cooling effect being partly provided by a fan 5 which may be driven by a motor 6. Condensed refrigerant is delivered from the condenser 4 to an expansion float device 7, and from thence to a sheet metal evaporator 8 through an inlet conduit 9 as refrigerant is vaporized in the evaporator 8 by the heat absorbed thereby, it is drawn back to the motor compressor casing 3, through a discharge conduit 11, and eventually to the compressor 1, whereupon the cycle is repeated.

I now refer specifically to figs. 2 to 5 for ade,- scription of my invention as applied, on one embodiment, to the sheet metal welded evaporator 8 shown in Fig. 1. The evaporator 8 comprises generally a main header 12 which is provided with end pieces 10 and a plurality of passageways 13 depending from and communicating with the header 12 and being formed between sheet metal walls 14 and 15, one of which is corrugated as shown at 16 to form the passageways 13.

The sheet metal walls 14 and 15 are preferably welded a their peripheries, and between th corrugation 16 to separate the passageways 13, and to impart rigidity to the evaporator 8.

The evaporator 8 is also provided with a header or passageway 17, remote from the main header 12, and preferably disposed at the bottom of the evaporator 8 as shown in Figs. 3 and 4. Preferably, all of the passageways 13 communicate with the lower header 17 so that free flow of refrigerant between passageways through the header 17 is possible. The inner wall 15 of the evaporator 8 is also preferably provided with bumps 24 for supporting ice tray supports (not shown).

As shown in Figs. 2 and 4, the refrigerant inlet conduit 9 extends through the main header 12, and is welded at 18 to one of the passageways, designated at 13a. before the header 12 is closed. The header 12 is preferably formed of four quarter circles of metal 12a, 12b, 12c, and 12d, each section being integral with one of the walls 14 or 15 as clearly shown in Fig. 4. The walls 14 and 15, with corrugations 16 in one of them are preferably welded between the corrugations when the sheets 14 and 15 are flat as shown in Fig. 6; the result is a fiat double ,wal1ed sheet having half circles at two opposite ends thereof each made up of substantially semi-circular segments 12b and 12c and 12a and 12d. The flat sheet is then bent into the shape shown in Fig. 4 and the header 12 is welded at 26 and 27. However, before the sheets are fully bent and the header 12 welded, the inlet conduit 9 is weld'ed to the passageway 13a at 18. The evaporator 8 is then fully bent and the header is welded at 26 and 27. The refrigerant discharge conduit 11 also extends through the main header 12 and has its end 19 disposed above the normal liquid refrigerant level, as shown in Figs. 2 and 4. The inlet and discharge conduits 9 and 11 are welded or brazed to the header 12 at their point of entrance, and preferably extend through an evaporator support 21 to the refrigerating unit.

When the refrigerating unit operates, usually in response to the temperature ofthe evaporator 8 through suitable control means (not shown) vaporized refrigerant which is boiled from the evaporator 8 and in which small quantities of oil are entrained, is drawn to the compressor 1 from the evaporator 8 through the discharge conduit 11. The oil lubricates the working parts of the refrigerator unit, and the refrigerant is compressed in the compressor 1. Refrigerant under high pressure, and small quantities of oil entrained therein are vdelivered to the condenser 4 where the refrigerant is cooled and condensed, the cooling being assisted bythe air draft caused by the fan 5.

Liquid refrigerant and oil are then delivered to the expansion oat device 7, and when it reaches a predetermined level therein, the float device allows refrigerant and oil to be delivered at low pressure to the evaporator 8 through the inlet conduit 9. The combined oil and refrigerant are conveyed immediately to the bottom of the evaporator 8 by means of the passageway 13a. They then circulate out through the lower header 17 and up the passageways 13, the majority of the oil normally rising to the top of the refrigerant contained in the evaporator 8. Some of the oil coats the walls of the evaporator 9, but due to the forced circulation of refrigerant, the oil will not Collect 0n the walls in large quantities even when the oil is thickened by the relatively low temperature in the evaporator. Forced circulation of refrigerant also keeps all parts of the evaporator 8 supplied with fresh liquid refrigerant, and the temperature in all parts of the evaporator is, therefore, maintained more uniform. Refrigerant vapor and oil are then again drawn back to the compressor from the evaporator 8, and the cycle is repeated.

From the foregoing, it will be apparent that I have provided an evaporator in which a forced circulation of refrigerant and lubricant is provided so that the temperature in the evaporator is maintained at an even low temperature, and oil logging, with consequent poor heat transfer through the evaporator, is substantially eliminated. It will also be apparent that I have provided a structure which is economical to manufacture and which is easily assembled for accomplishing' the above results.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications, without departing from the spirit thereof, and I desire. therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

, What I claim is;

1. A refrigerant containing evaporator of the flooded type which includes one upper header, a lower header, one or more chambers connecting and opening into the headers, refrigerant inlet 35 and discharge conduits passing through the upper header, one end of said discharge conduit being disposed in the upperM header, and means for conveying refrigerant from the inletfconduit directly to the lower header.

2. A refrigerant containing evaporator ofthe flooded type which -includes an upper header, a lower header, a plurality of closed chambers connecting and opening into the headers, refrigerant inlet and discharge conduits passing through the upper header, one end of the discharge conduit; being disposed in the upper header, the inlet conduit being connected directly to at least one of the chambers, whereby incoming refrigerant is conveyed directly to the bottoms of the remaining chambers through the lower header. I.

3. A refrigerant containing evaporator of the type comprising generally a header and corrugated welded walls extending from the header whereby passageways are formed by the corruga-f tions which passageways open into theheader, which includes a second header connecting substantially all of the passageways in fluid exchange relation, and an inlet conduit for conveying liquid refrigerant tothe evaporator, said inlet conduit being directly connected to at least one of the passageways, said second header being disposed below the first header and said inlet conduit extending through the first header and being connected to one or more of the passageways at the points where the passageways enter the first header.

4, In a refrigeratng system in which a refrigerant fiuid is vaporized, compressed and condensed, an evaporator embodying inner and outer sheet-metal shells disposed in closely spaced relation, one of said shells being corrugated and contacting, between the corrugations, with the other shell so as to form a series of verticallyextending, side-by-side, exposed refrigerant passages, a condenser, a conduit connecting with the condenser and with the upper portion of one of said exposed passages for supplying condensed refrigerant to the evaporator, valve means associated with said conduit for restricting the fiow of refrigerant from the condenser to the evaporator, a horizontally-extending dstributing header embodied in the evaporator and connecting the lower portion of the first-mentioned exposed passageway to the lower or inlet portions of the remaining exposed passageways, and outlet means for removing refrigerant vapor from the upper portions of said remaining exposedpassageways, whereby the refrigerant uid is circulated downwardly through one of the exposed passageways and upwardly, in multiple, through the remaining exposed passageways.

5. In a refrigerant containing evaporator for refrigerators, the combination of an upper header, corrugated welded walls depending from the upper header, said corrugations forming passageways opening into the header, a second header located below the upper header and connecting the lower ends of substantially all of the passageways, and an inlet conduit for conveying liquid refrigerant to the evaporator, said inlet conduit A extending into one of said passageways for conveying refrigerant fluid to the lower header and, therefore, to the lower ends of substantially all of the passageways, whereby the refrigerant fluid is circulated downwardly through one of the passageways and upwardly, in multiple, through a plurality of the passageways.

6. In a refrigerant containing evaporator for refrigerators, the combination of an upper header, corrugated welded walls depending from the upper header, said corrugations forming passageways opening into the header, a second header located below the upper header and connecting the lower ends of substantiallyall of the passageways, and an inlet conduit for conveying liqud refrigerant to the evaporator, said inlet conduit extending through the upper header and extending into one of the passageways where said passageway enters the upper header, whereby the refrigerant fluid is circulated downwardly through one of the passageways and upwardly, in multiple, through a plurality of the passageways.

7. A refrigerant containing evaporator for a refrigerator including flat sheets of metal dis posed adjacent to each other and welded together,

said assembled sheets forming two parallelvertical walls and a connecting bottom wall to provide an 4ice freezing chamber, corrugations `formed in one of the sheets to provide a series of vertically extending refrigerant passageways in the parallel walls, a header extending transversely of the passageways and interconnecting the passageways of both vertical walls, and an inlet conduit for conveying refrigerant to the evaporator, said inlet conduit extending into a passageway in one of the i140 vertical walls near the top thereof to convey refrigerant to said -header and from thence to other of the passageways, whereby refrigerant is circulated downwardly through one of the passageways, and upwardly through a plurality of said passageways in both vertical walls.

4FREDERIC L. TARLETON. 

